Method for ozone generation



6 Sheets-Sheet 1 INVENT OR ATTORNEYS I W. E. CROMWELL METHOD FOR OZONE GENERATION Oct. 21, 1958 Fild Oct. 20, 1955 Oct. 21,1958

Filed Odt. 20, 1955 ENERGY YIELD LBS. OZONE P W. E. CROMWELL METHOD-FOR OZONE GENERATION 6 Sheets-$het 2 EFFECT OF CARBON MQNOXIDE ON ENERGY YIELD VOLUME PERCENT CARBON MON OXIDE William E. Cromwell A'ITORNEYJ INVENTOR Oct. 21, 1958 w. E. CROMWELL METHOD FOR OZONE GENERATION 6 Sheets-Sheet 3 Filed 001;. 20, 1955 m! S N O 0 w V N O LN3DH3d EIWfi'lOA Nl HCIIXONOIN NOSHVD BITIVA DNIJJINII INVENTOR o .LN3DH3d HWDWOA NI BGIXONOW NOQHVD BH'IVA DNLLIWI'I Wil E Cromwell BYW, W vw ATTORNEYS Oct. 21, 1958 w. E. CROMWELL METHOD FOR OZONE GENERATION e Sheets-Sheei 4 Filed Oct. 20, 1955 2 I O 9 8 7 6 5 4 3 a 3 3 3 2 2 2 2 2 2 2 0 O. O O O. O. O O O. O 0

MQDF mum KI mun- MZONO mm: ZOFPUDQOIQ VOLUME PERCENT CARBON MONOXIDE IINVENTOR ATTORNEYS William E. C'romweLL.

%,Wu 9 My Oct. 21, 1958 w. E. CROMWELL 2,857,323

METHOD FOR OZONE GENERATION Filed 001;. 20, 1955 6 Sheb ts-Sheet 5 EFFECT OF CARBON MONOXIDE ON. ENERGY YIELD ENERGY YIELD LES. OZONE PER k.w.h. 8 (i VOLUME PERCENT CARBON MONOXIDE Fix; 7a. EFFECT OF CARBON MONOXIDE ON .TOTAL PRODUCTION OF OZONE TOTAL PRODUCTION LBS. OZO| \|E P ER H R. PE R TOBE o w O O.I 0.2 0.3 0.4 0.5

VOLUME PERCENT CARBON MONOXIDE INVENTOR William E. Crqmwell;

' ATTORNEYS ,W,WY

Oct. 21, 1958 Filed Oct. 20, 1955 w. E. cRoMwEEL" Man-1015 FOR OZONE GENERATION 6 Sheets-Sheet 6 Fig.8.

EFFECT OF CARBON MONOXIDE ON ENERGY YIELD O 0.2 0.4 0.6 0.8 1.0 L2 L4 L6 L8 2.0

VOLUME PERCENT CARBON MONOXIDE EFFECT OF CARBON MONOXIDE ON TOTAL PRODUCTiON OF OZONE 0.2 0.4 0.6 0.8 L0 1.2 .I.4 1.6 I.8- 2.0

VOLUME PERCENT CARBON MONOXIDE INVENTOR William E. Cromwell ATTORNEYS United States Patent C) METHOD FOR OZONE GENERATION William E. Cromwell, Titusville, N. 1., assignor to The Welsbach Corporation, Philadelphia, Pa., :1 corporation of Delaware Application ctober 20, 1955, Serial No. 541,681 2 Claims. (Cl. 204-176) This invention relates to methods and apparatus for ozone generation, and more particularly to suchmethods and apparatus in which gases heretofore considered as contaminants are employed to increase the energy yield of the apparatus with a resulting increase in the generation of ozone per kilowatt hour of energy supplied, or as total production, i. e. amounts of ozone produced by the ozone generator per unit time.

It has heretofore been generally accepted that the best yield of ozone is obtained by generating the ozone from pure oxygen, and that any admixture of foreign gases with the pure oxygen impaired the efliciency of the ozone generator and resulted in reduced ozone production. Contrary to this accepted belief and most unexpectedly it has been found thataddition's of small amounts of carbon monoxide to the oxygen actually increase the energy yield of ozone generation. This very important and unexpected discovery is the basis of the methods for ozone generation of the present invention for the apparatus employed for carrying out these methods.

It is accordingly an object of the present invention to provide novel methods and apparatus for ozone generation, in which increased eificiency, energy yield, is obtained in .the generation of ozone with increased productionv by'admixing small measured quantities of carbon monoxide with pure oxygen before it isadmitted to the ozonator. e

Another object of this invention is to provide methods andapparatus by-which an improvement upon previously designed apparatus of the same general nature is achieved by reason of the novel use of the admission of a foreign gas to the oxygen before use in an ozonator.

Another object of this invention is to provide methods and apparatus by which greater economy in the use of oxygen is achieved by retaining the unused gases from an, ozone consuming process and returning them to the.

ozonator.

,Another object is to provide novel methods and apparatus for ozone generation in which increased energy yield and increasedtotal production of ozone are obtained by regulating the amount of carbon monoxide present in the oxygen-bearing gases before admission to the ozonator.

The methods and apparatus of the. present invention are capable of various procedural and mechanical embodiments and the illustrative description thereof, hereinafter set forth, should in no way be construed as defining or limiting the present invention, reference being had to the appended claims to determine its scope.

The accompanying drawings show illustrative apparatus for carrying out one embodiment of the methods of the present invention, and-in these drawings in which like reference charactersindicate like parts,

Fig. 1 is a schematic representation of-suitable-apparatus for supplying measured quantities of pure oxygen and measured quantities of carbon monoxide to an ozonarived from a source not tor including apparatus for conveying the ozone-bearing gas to a process in which it is to be used, and for returning it for re-use in the ozonator, including apparatus for measuring the carbon monoxide concentration and an apparatus for measuring the ozone concentration;

Fig. 2 is a circuit diagram of a suitable circuit for supplying electrical energy to the ozonator of Fig. 1;

Fig. 3 is a graphic representation showing the increased energy yield of ozone compared to the volume percent of carbon monoxide employed;

Fig. 4 is a graphic representation of the limiting value of volume of carbon monoxide with respect to energy yield as compared to energy input;

Fig. 5 is a graphic representation showing the increase in total production of ozone as compared to the volume percent of carbon monoxide employed;

Fig. 6 is a graphic representation showing the limiting value of volume of carbon monoxide with respect to total production of ozone as compared to the energy input;

Fig. 7 is a graphic representation showing increased energy yield and Fig. 7a shows increased total production of ozone as compared to volume percent of carbon monoxide employed for values of carbon monoxide from A of 1% up to of 1%; and

Fig. 8 is a graphic representation showing increased energy yield andFig. 8a shows total production of ozone compared to the volume percent of carbon monoxide employed for values of carbon monoxide froniO up to 2%.

Referring 'now'more particularly to Fig. 1, it will there be seen that oxygen from any suitable source 19, which may be pure oxygen or an oxygen rich gas. mixture deprimarily utilized for the production of ozoneas Where oxygen is a by-product of a chemical reaction, is delivered through piping 20 to a valve 21 and to piping 22 which connects to a suitable gas volume measuring means for oxygen 23 which in turn connects to piping 24 and piping 24 connects to piping 25. Piping 25 connects to a suitable pressure regulating means 26 which is in turn connected by piping 27 to suitable gas drying means 28.

Carbon monoxide is obtained from a suitable source 13 which is connected by piping 14 to asuitable valve 15 which in turn is connected by piping 16 to a suitable gas volume measuring means for carbon monoxide 17. Measuring means 17 is connected by piping 18 to piping 25.

Gas drying means 28 is connected by piping 28 to a suitable ozonator 30 which is shown as of the discharge type. Gases including ozone are emitted from ozonator 30 at 96 and pass through piping 31, valve 32 and piping 33 to suitable ozone measuring means 34. These gases also pass through valve 36 and piping 37 to suitable total gas flow measuring means 38 and from total gas flow measuring means 38 the gases pass through piping 39 to any suitable ozone consuming process generally indicated at 40. Gases from the ozone consuming process 40 less Electric power is provided for ozonator 30 by the electric circuit shown diagrammatically in Fig. 2. In this circuit a suitable source of cycle alternating curb 3.4 watt-hrs. per P. 2.1.3.9. s..i. t

u: -r'n-fff' -i-xv-xe-rrr-v. wa tfh-g i 01th 3 4 rent is generally indicated at 50 and connected to starting contactor means 51, which connects by wiring 52 and 60 Production, 'Energy Volume to suitable current measuring means 53 and to a suitable Trial ggf g igi g g g low voltage lnductron coil 61, respectively. Means 53 'Per Tube. Per kwh. Monoxide is connected by wiring 54 to a suitable electric power I measuring means 55 and means 55 is connected by wiring 0. 0330 0.326 56 to volt meter 57, volt meter 57 bein ne ct ed ggg 3% Wiring 58 to'means 55 and to wiring n2, 1ng "62 con} :0336 I333 319 necting to induction coil 61. Power measuring means 8333 12?; i3 55 is connected by wiring 59 to the low voltage prirna r y. windings 67 of transformer 68 and the other side of windings 67 is connected to wiring 62. High voltage secondary windings 69 of transformer 68 are connected by wiring 78 and 73 to ozonator 30 and wiring 79 leads A L I to ground. A' high voltage induction coil 76 is connected l across wiring 78 and 79 by wiring 77 and 75, respectively. Oxygen and carbon monoxlde matures Ozonator 30 is ot the so-called .ozonator discharge type Date '55 and is well known being described in Encyclopediav of I V Chemical Technology, volume 9, 1952, pages 740-747, W2 790i; watts. among others. 0 1w 1' Ozonator'30 is made of stainless steel and is so. ar-

1 ranged that the. gas mixture is admitted at 9.1 from piping b 49 twatbhrs; 28" and passes through the space 92 between the jacket fl;

93 and glass dielectric 94. The ozone and other gases are emitted at 96 into piping 3 1 and 37, as described 25 I I i above. The hollow glass dielectric closed-end tube 94 is Trial internally coated with an electrically conducting material Pe Ha b q and theabove-described electric circuit is connected to Pet Tube Per kWh Monoxlde said coating through vwiring 78. Tube 94 is suitably Y spaced from jacket 93' to provide a'suitable corona dis- 1 918%. a :288 3' chargespace generally indicated at 92. Jacket 93 and I 2 ozonator are. grounded through wiring 79, as de- 1 7 scribed above. 333g g; g;

In the tables of data hereinafter the following'symbols 4 jo I 12 41o a employem 5 822?, t I 133% 2 j V=tota1 gas flow rate, cubic feet per minute per tube 7 reduced to 760 mm. Hg, 25 C. and dry. W =electric power, watts per tube corrected for meter and transformer losses. TABLE III P=absolute ozonator pressure, p. s. i. t ==temperature of cooling water, C. Oxygen and carbon monoxide mixtures nen atin wt-hrs. e c.ft.of b jgi f fi c U at p r H Date 8-18-55. B==energy yield of ozone generation, lbs. of ozone per V W3 7 91:]. watts.

When measured amounts of carbon monoxide are P 21.2 p. s. i. mixed with the oxygen admitted to ozonator 30 or when b 9.5. watt-hrs. per the carbon monoxide content of the oxygen rich gases i s cu. ft. adjusted before admission to the ozonator, a surprising a and unexpected increase in efiiciency of ozone generation Production Energy v 01mm is found when the carbon monox de content 1s mainta ned Trial Lbs. Ozone Yield, Percent at a certain optimum valueof the total volume ot the. aggag iif gf f ggggg mixed gases. The following tables employing the sym- I H a V hols described above, show the increased efficiency oi Q0242. 0.264 ozone generation when the quantity of carbon monoxide 1 .0243 .268 Q mixed h he xygen is controlled before admission to 2 :gfi fig 3 3 the ozonator in the processes and apparatus described 3 .0241 .262. 2.0.

.0237 .263 2.0 above. 0 4 .0229 .255 t 2.7

Various theories may be advanced for th s surpr s ng .0227 250 2.7 and unexpected result, but none can be proved and dis;

:33}? 2}; cussion of them is omitted. so as not to burden undu ly this specification.

TABLE 1 t I Oxygen and carbon monoxide mixtures TABLE Date 3- 5 Oxygen and carbon monoxide mixtures. V 0.49 s. c. f. m. Date 8-23-55. W ::1 watts. V 0.11 s. c. f. m. 1., 27 C W 91:1.watts. P 20.5. p. s. i. t 26 C.,

TABLE VIII Trial ggfggg: I 335? 2133? Oxygen and carbon monoxide mixtures t p gg gfi gag, at .8"1255.

1 l V 0.30 s. c. f. m.

o 3 L262 0 W2 watts.

.0239 .257, 0 1 g 27 C, 38 23 :52; $15 P 21.2 p. s. i. -83; g-g b 5.1 watt-hrs. per cu. ft. 10231 I252 012 10 0231 Production, Energy Volume Trial Lbs. Ozone Yield, Percent Pei-Hr. Lbs. Ozone Carbon Per Tube er kwh. Monoxide I I TABLE V 0. 29 0.212 0 Oxygen andcarbbn monoxide inixtures 1 g 0. :2 Date 8-4-55. 13 .1 3 1 1 v 0.33 8. e. rm. 7 a: .12. W2 2: We at; :22; tit w 32 .0311 .334 1. 72-

p. s. 1. p V W'fl From these tables and Fig. 3, it is apparent that the d i E 1 V energy yield, lbs. of ozone per kwh., increases substan- 0111 I nfirgy 0 25 tially as carbon monoxide is-present in the oxygen up to Trial L -P gfilizme 0.8%, up to 1.3%, and up to 1.5%, when the energy PePTllbe wPefkwh Monoxide input, Watt-hrs. per cu. ft. is 9.5, 4.9, and 3.4 respectively.v It is alsoapparent that some gain in the energy figg 8 yield can be'expected when carbon monoxide-is present 2 Z0339 .323- .10 in oxygen up to 1.7%, 4.1%, and 4.9% respectively. 0346 These limiting values of carbon monoxide are shown in Fig. 4, and are compared to energy input watt-hrs. per cu. ft. of gas treated.

From Fig. 4 it is apparent that no gain in energy yield TABLE VI can be expected from the presence of carbon monoxide in oxygen, when the energy input is greater than about 13 Oxygen carbon monoxide matures watt-hrs. per cu. it. This is verified by the data in Table Date IV and Fig. 3, where the energy yield is reduced by the V presence of carbon monoxide in oxygen when the energy W2 watts- 40 input is 14.1 watt-hrs. per cu. ft. w From Fig. 4 it is also apparent that some gain in energy P P- yield can be expected from the presence of carbon monoxb P ide in oxygen, up to values of about 6% by volume for energy input values of about unity. Productio E y Volume From these tables and Figs. 5 and 6, it is apparent that Tml f %f figi 53%;; some gain in ozone production as contrasted to energy For Tube Per kwh. Monoxide yield can be expected from the presence of carbon monoxide in oxygen. 1 .338; .393 3 From these Tables and Figs. 7 and 8 it is apparent that :0300 Q21 the energy yield and the total production of ozone in- 2 .0305 .3 1 0- 1 creases substantially as carbon monoxide is present in the a 1828: I 8:28 oxygen in increments as low as $5 of 1%.

Commercial oxygen available for use in ozonators contains no measurable quantities of carbon monoxide. It 55 is within the concept of this invention to control the amount of carbon monoxide by addition thereto, to obtain TABLE VII the above described advantages. Oxygen and carbon monoxide mixtures In the generation of ozone, the performance of the Date (L55. ozonator can be def ned in terms of total pounds of ozone V 030 s C. f m. produced per unit time. This is the product of the ozone 93+1 watts. concentration and the total gas flow rate. The power t 7 necessary to produce this ozone is measured according to 213 s. i well known electrical methods. The energy yield of an b fl per cu ft ozonator such as pounds of ozone per kilowatt-hour of electric power, can then be computed.

. The energy input, the ratio of the watt-hrs. of elec- Tflal $5 323}: 3 235? 8 ,332 tric power and the cu. ft. of gas treated, is an independent Per Hr. Lbs. zone Carbon variable. In the generation of ozone from ozonators Per Tube Per kwh which use large amounts of oxygen and electric power, 0 0294 0 320 0 the performance characteristics can be determined as a 10295 1 0 function of the energy input.

gig 8 It is therefore within the concept of the present inven- 10309 1 0. 47 tion to control the carbon monoxide content of the oxygen -0309 gas mixture within certain limiting values as discussed above, which are determined by energy input values, in

zgsmyaaa-i 1 order to obtain the unexpected, increase in energy yield and total production; of ozone. I p

In the generation and use of ozone in amounts of several tons per day, the gas mixture -after passing-fromthe ozonatorand after use of the'ozone maybe-recycled to the ozonatonas through-pi ing ZS- (-Fig, 1 The" recycled gas mixture haslosasome oxygen(-tothe-ex? tent of the ozone produced-and usedyandmay. and: usually does containcontaminants-which should bere moved. It is therefore within the conceptof -the'pr-esent invention to control the carbon monoxide content of this, recycled oxygen gas mixture, to some optimum value as discussed above, to( obtain the unexpected increase of energy yieldandproductionof ozone. This controlisiobtained by removal iofncarbon monoxide in excess of these optimum limits,- onby addition of carbon monoxide or of oxygen to bring the gas: mixture to the desired optimum composition. v

It will now be apparent that :by the present invention novel methods and apparatus for the generation of ozone, employing small amounts of carbon monoxide with increased efficiency of ozone generation has been providedwhich in every' way satisfies thepobiects. of'this :inventiom.

Changes in: or modifications to. the above described% illustrative embodiment of the methods and apparatus: of:

this invention may now beusuggested to those; skilled in' the art without, departing. from: the: present inventive: concept, and reference: should, be had: to the appended claims toidetermine the scope thereof..

What claimed is:.

1. In.--a method font increasing the energy yield of ozonegeneratibmhy a qorona-type discharge ozonator continuously" supplied withfloxygen, the ratio of supplied watt-hrs. pen-ecu. ft. o-=gas treated, the step of continuously mixing i lfrom Oilto 6.1% by volume of carbon monoxide with the oxygen befbrecontinuous admission to the ozonator.

10 2'. In a method fon increasingthe energy yield of ozone generation by a corona -type discharge ozonator continuously" supplied with an oxygen-gas mixture, theratio of supplied electric power to oxygen being in the range from 1-13 watt-hrs. per cu. ft. of gas treated, the step 15. of continuously controlling the content of carbon monoxide in the gas.mixture to lwithinuthe range of from 0.1 to 6.1% by volume of carbon monoxide.

References fire-am are are of-"thi's patent' OFIHERLREEERENCES La Cuux: L fizone et ses Applications Industrielles (1904)", pp, 10916112.

Pinkus at 211.: Journal de Chemie Physique, vol. 24 30 (1927), pp..3;70 to 3.9011

,: electrictpower tor-oxygenbeingin therange from 1 -to- 13- 

1. IN A METHOD FOR INCREASING THE ENERGY YIELD OF OZONE GENERATION BY A CORONA-TYPE DISCHARGE OZONATOR CONTINUOUSLY SUPPLIED WITH OXYGEN, THE RATIO OF SUPPLIED ELECTRIC POWER TO OXYGEN BEING IN THE RANGE FROM 1 TO 13 WATT-HRS. PER CU. FT. OF GAS TREATED, THE STEP OF CONTINU- 